Want to clean my 03 cummins under the hood but not sure how. Thought about mean green and hose but see some type of electrical box on the side of the block in front of fuel filter. Also see one on the pass side firewall and of course the fuse box but that is easy to wok around. Would like to get you guys input and experience so I dont make a costly mistake. I would rather have a dirty engine than a clean one that leaves me on the side of the road!! Thanks for any input.

 

I've always just hit mine with a pressure washer (either at home or at a car wash). I try not to spray the electrical box directly but it'll still get a little wet; knock on wood I've never had a problem with any of my vehicles. I did knock a coil wire off a gasser once but aside from that no problems at all.

On a similar note I wouldn't spray down a hot engine; I'd make sure it's cooled off.

 

I try to clean most of mine by hand or at last the large items, Valvecover, Airbox lid, batteries, etc. The airbox lid is actually easy enough to remove and clean off of the vehicle. If I do use the hose underneath the hood, I make sure it is low pressure and low flow while avoiding all of the electronics possible (alternator, connectors, etc.) On a 3rd gen, it isn't exactly an easy task.

 

Like said by DrewGzy, Not ever a problem...

 

I've made a point of keeping every vehicle I've ever owned spotless under the hood. They've always had a good bath with high pressure every time the vehicle gets a wash and I've never had a problem. I do it with a cool engine, and avoid direct lengthy blasts to the alternator and electrical connectors.

 

Self serve car wash and a can of Gunk engine brite. Becareful of the obvious stuff. Like after market open air cleaner. Never had an issue. Not saying i couldnt but a step back or 2 and you cut down the pressure

 

I like spraying her down with some of the purple junk and it rinses away nicely

 

i asked the same question this summer and got many similar responses. i used simple green put bags over ecm/fuse block and taped off as many electrical connections as i could find. I'm still trying to get rid of some codes been a nightmare. sounds like a lot of people have no problems but i will never be washing mine again!

 

I did mine this weekend to get the salt off of everything. Did under the hood and under the whole vehicle.

I used a small pressure washer with a broad spray. Probably had it set around 800 psi or so. Did great no issues.

I use Gunk spray on for degreasing but notice even with pressure washing it does not do a great job unless worked in with a brush.